Cannot receive own email messages

[AK16]

Out of the blue, we are suddenly unable to receive email messages that we send from our email address to to our own inbox.  We watch them hit the inboxes in Microsoft 365 and Outlook and then disappear from each within a fraction of a second.  They appear in the sent boxes of M365 and Outlook, but are no where to be found otherwise.  This is a sudden occurrence after successfully being able to send messages to ourselves via the "to", "cc", and "bcc" fields until now.  Thank you, kindly, for any assistance you can provide.

[Muse]

@AK16 

Did you make any changes to your settings or add any filters or rules?  Sometimes they have unintended consequences. That is the only thing I can think of that would redirect emails.  You can check if there is something in place causing this by going to the File tab > Manage Rules & Alerts.  😉